[kfriede]

My driveshaft has hummed/vibrated for a while now. I finally took it to the shop thinking it was the u-joints, but they are saying that it is likely the bearing in the cardan joint. Their quote was unreasonably high, and I came across Tom Wood's for a reasonable price.

My question is, can I drive my current driveshaft to failure without worrying about it damaging anything else? I recently replaced the 3rd member and don't want this to take out that bearing from vibration, but also don't mind the vibration if I can push this off until later.

[dogtail]

DC joint is an easy rebuild by someone that knows what they are doing. Its a simple needle bearing joint. A fully rebuilt shaft and balance costs me $235. I've put a lot of miles on my current one since rebuild without issues. You can also hunt a used shaft in a scrap yard for maybe $75ish.
Shaft vibrations can give the pinion bearing a beating, so try to do something asap.
Here's my write up on DC rebuild.
Double Cardan rebuild

[mtbtim]

Originally Posted by dogtail

DC joint is an easy rebuild by someone that knows what they are doing. Its a simple needle bearing joint. A fully rebuilt shaft and balance costs me $235. I've put a lot of miles on my current one since rebuild without issues. You can also hunt a used shaft in a scrap yard for maybe $75ish.
Shaft vibrations can give the pinion bearing a beating, so try to do something asap.
Here's my write up on DC rebuild.
Double Cardan rebuild

How many miles do you have on your rig after the driveshaft work? Remember I commented on your write-up and was interested in possibly doing a double cardan rebuild video myself? There's a driveline shop near me in San Jose, CA and the owner has over 30 years in the business. I asked his opinion about rebuilding the double cardan joint and he told me he doesn't do it because the replacement parts available aren't that great. He said Neapco use to be of higher quality, but once operations went overseas, the quality went way down in his opinion. It's hard not to listen to a guy who's been in the business for that long and obviously knows his trade. But, he's just one opinion and that's why I'm wondering how many miles you've got on that rebuilt driveshaft now. Have you gotten underneath your rig and inspected the joint for any play?

[dogtail]

Originally Posted by mtbtim

How many miles do you have on your rig after the driveshaft work? Remember I commented on your write-up and was interested in possibly doing a double cardan rebuild video myself? There's a driveline shop near me in San Jose, CA and the owner has over 30 years in the business. I asked his opinion about rebuilding the double cardan joint and he told me he doesn't do it because the replacement parts available aren't that great. He said Neapco use to be of higher quality, but once operations went overseas, the quality went way down in his opinion. It's hard not to listen to a guy who's been in the business for that long and obviously knows his trade. But, he's just one opinion and that's why I'm wondering how many miles you've got on that rebuilt driveshaft now. Have you gotten underneath your rig and inspected the joint for any play?

No so sure about that his opinion or quality of work, shops can run a wide range on workmanship quality no matter how many years in business. I've found a lot of fake news opinions throughout my years.
Regarding your guys statement of Neapco overseas manufacturing, my DC rebuild post has "Made in USA" stamped right on the Neapco box (see pic). But some of their parts may be made outside of the US. Made overseas is not necessarily a bad thing either, there is a lot of good manufacturing going on outside of the US, and companies monitor the quality to spec. If a company cuts corners and goes for the low bid, yeah quality can tank.
I do about 1,000 miles a week on my dd, so I'd say about 30Kish on the shaft rebuild. No vibration, tight and I check it on regular lubing at oil changes. I have 906 rear springs with 99 talls in front, so it has some rake. I do a lot of highway miles without shaft vibration.
I like having a spare shaft, and good idea for a serious 3rd gen enthusiast and can be grabbed cheap at a scrap yard.
My experience so far is good, but I have a good driveline shop that does these DC rebuilds all the time. Last time I went there they had a customers 3rd gen shaft right at the front desk. Those were the last pics in my rebuild post. Somebody else may not have my good results. There are variables in workmanship, attention to detail, and measurement of the stud shaft wear specs.

[repo]

Freeway driveline failure + aftermath

[madbomber08]

When greasing the DC joint, are you able to see grease coming out of it? Every time I try to grease it, grease just piles up around the outside of the zerk. Also I checked the ball detent on the zerk and it is free. All the other U joints take grease but it appears the DC won't. Any suggestions?

[dogtail]

Originally Posted by madbomber08

When greasing the DC joint, are you able to see grease coming out of it? Every time I try to grease it, grease just piles up around the outside of the zerk. Also I checked the ball detent on the zerk and it is free. All the other U joints take grease but it appears the DC won't. Any suggestions?

Its just needle bearings just like the U-joints. You should hear that crackling noise of the grease squeezing out just like a U-joint. Is your gun tip in good shape getting a good grab/seal? It should be able to get a good seal and build pressure. Also you maybe all dried/clogged up in the DC joint.
You can try a new grease gun tip or a needle tip, either way it should not blow "out thru the in door" of the zerk.

[kfriede]

Originally Posted by repo

Freeway driveline failure + aftermath

That's enough reason for me to replace it.

[kfriede]

Originally Posted by dogtail

No so sure about that his opinion or quality of work, shops can run a wide range on workmanship quality no matter how many years in business. I've found a lot of fake news opinions throughout my years.
Regarding your guys statement of Neapco overseas manufacturing, my DC rebuild post has "Made in USA" stamped right on the Neapco box (see pic). But some of their parts may be made outside of the US. Made overseas is not necessarily a bad thing either, there is a lot of good manufacturing going on outside of the US, and companies monitor the quality to spec. If a company cuts corners and goes for the low bid, yeah quality can tank.
I do about 1,000 miles a week on my dd, so I'd say about 30Kish on the shaft rebuild. No vibration, tight and I check it on regular lubing at oil changes. I have 906 rear springs with 99 talls in front, so it has some rake. I do a lot of highway miles without shaft vibration.
I like having a spare shaft, and good idea for a serious 3rd gen enthusiast and can be grabbed cheap at a scrap yard.
My experience so far is good, but I have a good driveline shop that does these DC rebuilds all the time. Last time I went there they had a customers 3rd gen shaft right at the front desk. Those were the last pics in my rebuild post. Somebody else may not have my good results. There are variables in workmanship, attention to detail, and measurement of the stud shaft wear specs.

So with the variation in workmanship quality, seems better to just replace. $75 junkyard part sounds better than $500 new, depending on how much would go out shortly after.

[dogtail]

Originally Posted by kfriede

So with the variation in workmanship quality, seems better to just replace. $75 junkyard part sounds better than $500 new, depending on how much would go out shortly after.

Yeah a used shaft is a nice alternative. One with decent mileage thats been lubed regularly can hold up a long time. Also they can get out of balance, which they re-balance on rebuilds. DC joint can easily hold up over 300K on a stock setup. I have an abundant supply of used shafts in my rust belt region cause so many rigs scraped.
One thing you can do to verify the vibration is in fact the shaft and not something else, besides doing a general feel test, is to pull out driveshaft and drive in front wheel drive in 4Hi.
Sometimes looking for rear drive train issues, I jack up the rear end having it running in drive and have somebody giving it gas while I'm underneath.